The holidays can be a grueling time for office workers, who must survive the ennui-filled purgatory between Thanksgiving and Christmas, recover from the boozy and body-wrecking holiday party circuit and fight off germs from the 80% of colleagues who come in to work despite being sick.

Out of that group who hit the cubicle while still battling sniffles and coughs, more than a quarter say they do it to avoid using a sick day. And among the workers who stay home to get over the worst of their symptoms, more than two-thirds return to the office while they're still contagious, according to a recent survey from office supply chain Staples.

Each year, the flu results in 70 million missed workdays and $10 billion in lost office productivity. March Madness, by comparison, causes employers to pay out $1 billion in wages to distracted workers.

Blame the weakened immune systems on filthy office behavior. Half of employees don't clean their work spaces once a week or more, according to the Staples report. Workers would do well to avoid, or give a vigorous scrubbing to, especially dirty areas such as computer keyboards and the break-room sink and microwave.

Then there's the matter of holiday parties, whether hosted by work or not. Nearly two-thirds of Americans have either called in sick or know someone who has ditched work to tend to a hangover after a seasonal fete, according to a report by Caron Treatment Centers.

Such celebrations can be a huge productivity suck, according to the nonprofit addiction treatment establishment. In the aftermath of a holiday party, many employees arrive late and leave early from work, are distracted in the office, take longer lunch breaks or are sick at their desks.

"There is already a significant amount of stress and competition in the workplace," Dr. Harris Stratyner, Caron's vice president, said in a statement. "If employees are unable to perform because of drinking too much the night before, their job performance may be seriously impacted."

It's a risk employers seem willing to take this year.

More than 83% are planning year-end parties, up from 68% last year and nearing the pre-recession standard of 90%, according to a report from consultant firm Challenger, Gray & Christmas Inc.

In a rare demand that Fiat Chrysler Automobiles buy back as many as 193,000 flawed vehicles, the top U.S. traffic safety agency signaled a tougher stance on automakers that don't identify and quickly repair defects.